1,596 research outputs found
A quantitative central limit theorem for the effective conductance on the discrete torus
We study a random conductance problem on a -dimensional discrete torus of
size . The conductances are independent, identically distributed random
variables uniformly bounded from above and below by positive constants. The
effective conductance of the network is a random variable, depending on
, and the main result is a quantitative central limit theorem for this
quantity as . In terms of scalings we prove that this nonlinear
nonlocal function essentially behaves as if it were a simple spatial
average of the conductances (up to logarithmic corrections). The main
achievement of this contribution is the precise asymptotic description of the
variance of .Comment: 37 page
On Random Field Induced Ordering in the Classical XY Model
Consider the classical XY model in a weak random external field pointing
along the axis with strength . We study the behavior of this
model as the range of the interaction is varied. We prove that in any dimension
and for all sufficiently small, there is a range
so that whenever the inverse temperature is larger than
some , there is strong residual ordering along the
direction.Comment: 30 page
Geodesics of Random Riemannian Metrics
We analyze the disordered Riemannian geometry resulting from random
perturbations of the Euclidean metric. We focus on geodesics, the paths traced
out by a particle traveling in this quenched random environment. By taking the
point of the view of the particle, we show that the law of its observed
environment is absolutely continuous with respect to the law of the random
metric, and we provide an explicit form for its Radon-Nikodym derivative. We
use this result to prove a "local Markov property" along an unbounded geodesic,
demonstrating that it eventually encounters any type of geometric phenomenon.
We also develop in this paper some general results on conditional Gaussian
measures. Our Main Theorem states that a geodesic chosen with random initial
conditions (chosen independently of the metric) is almost surely not
minimizing. To demonstrate this, we show that a minimizing geodesic is
guaranteed to eventually pass over a certain "bump surface," which locally has
constant positive curvature. By using Jacobi fields, we show that this is
sufficient to destabilize the minimizing property.Comment: 55 pages. Supplementary material at arXiv:1206.494
Thermophoresis of Brownian particles driven by coloured noise
The Brownian motion of microscopic particles is driven by the collisions with
the molecules of the surrounding fluid. The noise associated with these
collisions is not white, but coloured due, e.g., to the presence of
hydrodynamic memory. The noise characteristic time scale is typically of the
same order as the time over which the particle's kinetic energy is lost due to
friction (inertial time scale). We demonstrate theoretically that, in the
presence of a temperature gradient, the interplay between these two
characteristic time scales can have measurable consequences on the particle
long-time behaviour. Using homogenization theory, we analyse the infinitesimal
generator of the stochastic differential equation describing the system in the
limit where the two characteristic times are taken to zero; from this
generator, we derive the thermophoretic transport coefficient, which, we find,
can vary in both magnitude and sign, as observed in experiments. Furthermore,
studying the long-term stationary particle distribution, we show that particles
can accumulate towards the colder (positive thermophoresis) or the warmer
(negative thermophoresis) regions depending on the dependence of their physical
parameters and, in particular, their mobility on the temperature.Comment: 9 pages, 4 figure
Ιστορική και πολεοδομική εξέλιξη της πόλης του Βερολίνου - Συγκριτική μελέτη αναβάθμισης υποβαθμισμένων περιοχών σε Αθήνα και Βερολίνο
130 σ.Αντικείμενο της διπλωματικής εργασίας είναι η ιστορική αναδρομή και πολεοδομική εξέλιξη της πόλης του Βερολίνου από την ίδρυσή της μέχρι σήμερα, όπως και η σύγκριση δύο πρώην υποβαθμισμένων περιοχών που αναβαθμίστηκαν τις τελευταίες δύο δεκαετίες, σε Βερολίνο και Αθήνα αντίστοιχα. Η περιγραφή αυτή έχει ως σκοπό την παρουσίαση της σπουδαιότητας και του ρόλου του Βερολίνου δια μέσου των αιώνων, την επισήμανση των πολιτικών, νομοθετικών και πολεοδομικών γεγονότων και εξελίξεων που έπαιξαν σημαντικό ρόλο στην πορεία του, καθώς και τον εντοπισμό ομοιοτήτων και διαφορών από την ανάλυση της σύγκρισης των δύο περιοχών μελέτης.
Η παρούσα διπλωματική εργασία αποτελείται από έξι κεφάλαια.
Στο Κεφάλαιο 1 δίνονται γενικές πληροφορίες για το Βερολίνο, περιγράφοντας τη γεωγραφική θέση και έκταση, το κλίμα, τον πληθυσμό, τα δημογραφικά στοιχεία και την διοικητική διαίρεση της πόλης.
Στο Κεφάλαιο 2 παρουσιάζεται η ιστορική αναδρομή του Βερολίνου από την ίδρυση του το 1237 μέχρι και σήμερα, επισημαίνοντας τα σημαντικότερα ιστορικά γεγονότα.
Στο Κεφάλαιο 3 αναλύονται πολεοδομικά σχέδια (Σχέδια Χρήσης Γης), που έπαιξαν σημαντικό ρόλο στην εξέλιξη του Βερολίνου, ως προς τον σκοπό, το περιεχόμενο και τις επιπτώσεις τους, περιγράφοντας παράλληλα την πολιτική, νομοθετική και πολεοδομική εξέλιξη της πόλης.
Στο Κεφάλαιο 4 εξετάζεται η αναβάθμιση της περιοχή μελέτης Warschauer Straße του Βερολίνου.
Στο Κεφάλαιο 5 εξετάζεται η αναβάθμιση της περιοχής μελέτης του Γκαζιού της Αθήνας.
Στο Κεφάλαιο 6 περιλαμβάνονται τα συμπεράσματα και τα αποτελέσματα της σύγκρισης των δύο περιοχών μελέτης.Subject of the thesis is the historical overview and urban development of the city of Berlin from its foundation until today, as well as the comparison of two formerly degraded areas that have been upgraded over the past two decades, in Berlin and Athens respectively. This description is intended to show the importance and role of Berlin through the ages, highlight political, legislative and planning events and developments that played an important role in its course, and identify similarities and differences from the comparison analysis of the two study areas.
This thesis consists of six chapters.
Chapter 1 contains general information about Berlin, describing the geographical location and area, climate, population, demographics and administrative division of the city.
Chapter 2 presents the historical overview of Berlin from its founding in 1237 until today, highlighting the most important historical events.
In Chapter 3 we continue with the analysis of the aim, the contents, and the impact of urban plans (Land Use Plans), which played an important role in the evolution of Berlin, while describing the political, legislative and urban development of the city.
Chapter 4 examines the upgrade of the study area Warschauer Straße, Berlin.
Chapter 5 examines the upgrade of the study area of Gazi, Athens.
Chapter 6 gives the conclusions and results of the comparison of the two study areas.Βασίλειος Σ. Βλάχο
A Synopsis of The Tabanidae of Nebraska with a Description of a New Species from Colorado
Recently, the writer has had occasion to prepare a synopsis of the species of Tabanidae, otherwise known as horseflies, deerflies or gadflies, of the State of Nebraska. These flies are of importance to the farmer and stock raiser because of their blood-sucking propensities and their annoyance to stock. They breed in marshy lands and wet soil. This synopsis is based altogether on specimens collected in Nebraska and now actually present in the University of Nebraska collection. It is not probable, therefore, that it is a complete list. More extensive collecting over the state would probably reveal the presence of other species, since very little time has been spent in especially collecting these insects.
The classification of Hine has been followed in the main, but in listing the species those that are closely related have been brought together. The writer is indebted to Professors Myron H. Swenk and R. W. Dawson of the University of Nebraska, who have made possible the preparation of this paper. Acknowledgement should also be made to the works of Professor James S. Hine and Baron C. R. Osten Sacken on the Tabanidae, since these have contributed greatly toward the satisfactory identification of the species and the synoptic work
Towards a Complex, Active, Human-Centered Subject Grounded in the Sociopolitical: A Symbiosis of Edmund Husserl and Michael Foucalt
This thesis responds to the questions With the empirical, \u27found\u27 world prevalent as the paradigm for all valid knowledge, what happened to the relevance of the human in knowledge? Is there an alternative that does not divorce the knower from the knowing? The ideas of Edmund Husserl (1859-1938) and Michel Foucault (1926-1984), two thinkers traditionally viewed as rivals in continental philosophy and social theory, animate these questions. Both philosophers critique the taken-for-granted aspects of the world: Husserl through the constituting subject and Foucault through the socially, linguistically, and historically constituted subject. Rather than an either-or that oversimplifies the subject, a dialogue and a symbiosis between these two thinkers point to the foundation of an active, meaning-endowing subject in which this subject is enmeshed in inter-subjective power relations and in which certain knowledges are subjugated to others. Through a combined critique, it is possible to continue an investigation beyond a discursive level, to desediment more layers of knowledge, and to continue to critique the always-already there in order to understand enduring constitutions and the subject\u27s becoming
Calculations of the Knight Shift Anomalies in Heavy Electron Materials
We have studied the Knight shift and magnetic susceptibility
of heavy electron materials, modeled by the infinite U Anderson model
with the NCA method. A systematic study of and for
different Kondo temperatures (which depends on the hybridization width
) shows a low temperature anomaly (nonlinear relation between and
) which increases as the Kondo temperature and distance
increase. We carried out an incoherent lattice sum by adding the of
a few hundred shells of rare earth atoms around a nucleus and compare the
numerically calculated results with the experimental results. For CeSn_3, which
is a concentrated heavy electron material, both the ^{119}Sn NMR Knight shift
and positive muon Knight shift are studied. Also, lattice coherence effects by
conduction electron scattering at every rare earth site are included using the
average-T matrix approximation. Also NMR Knight shifts for YbCuAl and the
proposed quadrupolar Kondo alloy Y_{0.8}U_{0.2}Pd_{3} are studied.Comment: 31 pages of RevTex, 22 Postscript figures, submmitted to PRB, some
figures are delete
Primary vs. Secondary Antibody Deficiency: Clinical Features and Infection Outcomes of Immunoglobulin Replacement
<div><p>Secondary antibody deficiency can occur as a result of haematological malignancies or certain medications, but not much is known about the clinical and immunological features of this group of patients as a whole. Here we describe a cohort of 167 patients with primary or secondary antibody deficiencies on immunoglobulin (Ig)-replacement treatment. The demographics, causes of immunodeficiency, diagnostic delay, clinical and laboratory features, and infection frequency were analysed retrospectively. Chemotherapy for B cell lymphoma and the use of Rituximab, corticosteroids or immunosuppressive medications were the most common causes of secondary antibody deficiency in this cohort. There was no difference in diagnostic delay or bronchiectasis between primary and secondary antibody deficiency patients, and both groups experienced disorders associated with immune dysregulation. Secondary antibody deficiency patients had similar baseline levels of serum IgG, but higher IgM and IgA, and a higher frequency of switched memory B cells than primary antibody deficiency patients. Serious and non-serious infections before and after Ig-replacement were also compared in both groups. Although secondary antibody deficiency patients had more serious infections before initiation of Ig-replacement, treatment resulted in a significant reduction of serious and non-serious infections in both primary and secondary antibody deficiency patients. Patients with secondary antibody deficiency experience similar delays in diagnosis as primary antibody deficiency patients and can also benefit from immunoglobulin-replacement treatment.</p></div
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